单项选择题
Air temperature varies with（）.
A.the altitude above sea level B.the season of the year C.the latitude or distance from the equator D.All of the above
单项选择题 After a liferaft is launched，the operating cord（）.
单项选择题 Advection fog may be formed by cold air passing over a（）.
单项选择题 A sea anchor is（）.
